Display device and method of measuring surface structure thereof

ABSTRACT

A display device and a method of measuring a surface structure of the same are provided. The display device includes first and second substrates, first and second patterned light-shielding layers, and first and second pixel units. The first patterned light-shielding layer disposed on a surface of the first substrate includes first openings. The second patterned light-shielding layer disposed on the surface of the first substrate in the first patterned light-shielding layer includes second openings. The first pixel unit includes first and second protrusions. The first protrusion correspondingly covers the first openings and a portion of the first patterned light-shielding layer. The second protrusion is disposed in the first and second patterned light-shielding layers. The second pixel unit includes a third protrusion correspondingly covering the second openings and a portion of the second patterned light-shielding layer, wherein sizes of the second openings are smaller than sizes of the first openings.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan applicationserial no. 98140917, filed on Nov. 27, 2009. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of specification.

FIELD OF INVENTION

The invention is related to a display device and a method of measuring asurface structure thereof, and is particularly related to a surfacestructure of a display device and a method of measuring a size of thesame, which is applying to the field of display device.

DESCRIPTION OF RELATED ART

Recently, the trend of the display products is light, thin, small, andhigh resolution. However, these requirements cause difficulties indesign, fabrication and size measurement of the internal structures ofthe display device. That is, in order to dispose more pixels in asmaller space to provide a higher resolution, the interval space betweenthe structures is not sufficient. Therefore, the precision and thereproducibility of the size measurement results of the structures arepoor. Furthermore, it is difficult to control the processes by adjustingthe parameters according to the size measurement results, thus theproduction yield and the throughput are reduced.

FIG. 1 is a schematic view of a display device and an optical measuringapparatus for a surface structure. Referring to FIG. 1, the displaydevice includes a first substrate 210, a patterned light-shielding layer214, at least one first protrusion 218, and at least one secondprotrusions 2184. The first substrate 210 has a first surface 212. Thepatterned light-shielding layer 214 has a plurality of openings 216 anddisposed on the first surface 212 of the first substrate 210. The firstprotrusion 218 correspondingly covers the openings 216 of the patternedlight-shielding layer 214 and a portion of the patterned light-shieldinglayer 214. The second protrusions 2184 are disposed in the patternedlight-shielding layer 214. The optical measuring apparatus for a surfacestructure (not shown) includes a positional movable platform (notshown), a light source (not shown), an operation processing unit (notshown), and a microscope lens 100, and the microscope lens 100 includesa dichroic mirror (not shown), a first light detector (not shown), and asecond light detector (not shown).

FIG. 2 is a schematic cross-sectional view of the optical measuringapparatus for a surface structure and the first substrate 210 of thedisplay device along line A-A′ in FIG. 1. Referring to FIG. 2, thepositional movable platform carries the first substrate 210 of thetested display device to posit the microscope lens 100 directly over thepatterned light-shielding layer 214 on the first substrate 210. Thelight source emits a parallel light beam 102 toward the patternedlight-shielding layer 214, and the parallel light beam 102 is dividedinto a measuring light beam and an interference light beam by thedichroic mirror. The measuring light beam irradiates the patternedlight-shielding layer 214 on the first substrate 210, a reflected lightreflected from the patterned light-shielding layer 214 to the microscopelens 100 is received and converted into a first signal by the firstlight detector, and the interference light beam is received andconverted into a second signal by the second light detector.

FIG. 3 is a schematic cross-sectional view of the optical measuringapparatus for a surface structure and the first substrate 210 of thedisplay device along line A-A′ in FIG. 1. Referring to FIG. 3, thepositional movable platform is moved to posit the microscope lens 100directly over the first protrusion 218 on the first surface 212 of thefirst substrate 210. The light source emits a parallel light beam 102toward the first protrusion 218, and the parallel light beam 102 isdivided into a measuring light beam and an interference light beam bythe dichroic mirror. The measuring light beam irradiates the firstprotrusion 218 of the first substrate 210, a reflected light reflectedfrom the first protrusion 218 to the microscope lens 100 is received andconverted into a third signal by the first light detector, and theinterference light beam is received and converted into a fourth signalby the second light detector.

FIG. 4 is a schematic cross-sectional view of the optical measuringapparatus for a surface structure and the first substrate 210 of thedisplay device along line A-A′ in FIG. 1. Referring to FIG. 4, thepositional movable platform is further moved to posit the microscopelens 100 directly over the second protrusion 2184 on the first surface212 of the first substrate 210. The light source emits a parallel lightbeam 102 toward the second protrusion 2184, and the parallel light beam102 is divided into a measuring light beam and an interference lightbeam by the dichroic mirror. The measuring light beam irradiates thesecond protrusion 2184 of the first substrate 210, a reflected lightreflected from the second protrusion 2184 to the microscope lens 100 isreceived and converted into a fifth signal by the first light detector,and the interference light beam is received and converted into a sixthsignal by the second light detector. The first signal, the secondsignal, the third signal, the fourth signal, the fifth signal, and thesixth signal are received and operated by the operation processing unitto output the height of the first protrusion 218 and the height of thesecond protrusion 2184 on the first surface 212 of the first substrate210.

However, in order to dispose more pixels in a smaller space to provide ahigher resolution, a width of the light-shielding layer disposed betweenthe pixels should be reduced. Therefore, the light-shielding layer cannot provide a single plane having a sufficient width, and an uniformreflected light is not obtained as the measuring light beam irradiatesthe patterned light-shielding layer 214. Accordingly, the precision andthe reproducibility of the size measurement results of the structuresare poor. Furthermore, it is difficult to control the processes byadjusting the parameters according to the size measurement results, thusthe production yield and the throughput are reduced.

SUMMARY OF THE INVENTION

One of the objectives of the invention is to provide a display deviceand a method of measuring a surface structure thereof, so as to avoidreduced production yield and throughput caused by poor precision andreproducibility of the size measurement results of the structures asusing the conventional method.

The invention provides a display device and a method of measuring asurface structure thereof. The display device includes a firstsubstrate, a first patterned light-shielding layer, at least one secondpatterned light-shielding layer, at least one first pixel unit, at leastone second pixel unit, and a second substrate. The first substrate has afirst surface. The first patterned light-shielding layer includes aplurality of first openings and is disposed on the first surface of thefirst substrate. The second patterned light-shielding layer includes aplurality of second openings and is disposed on the first surface of thefirst substrate in the first patterned light-shielding layer. The firstpixel unit includes at least one first protrusion and at least onesecond protrusion. The first protrusion correspondingly covers the firstopenings of the first patterned light-shielding layer and a portion ofthe first patterned light-shielding layer. The second protrusion isdisposed in the first patterned light-shielding layer and the secondpatterned light-shielding layer. The second pixel unit includes at leastone third protrusion. The third protrusion correspondingly covers thesecond openings of the second patterned light-shielding layer and aportion of the second patterned light-shielding layer, wherein sizes ofthe second openings of the second patterned light-shielding layer aresmaller than sizes of the first openings of the first patternedlight-shielding layer. The second substrate has a second surface and isdisposed opposite to the first surface of the first substrate. The firstsubstrate of the display device of the invention includes at least onelight-shielding layer having a width larger than a width of the otherlight-shielding layers. Therefore, the first substrate provides anuniform reflector plane to an optical measuring system to obtainmeasurement results with high precision and high reproducibility.Accordingly, precise data is provided to control the processes which areadjusted by the parameters according to the size measurement results,thus the production yield and the throughput are increased.

Another objective of the invention is to provide a method of measuring asurface structure of a display device. The method includes the followingsteps. A display device is provided. The display device includes a firstsubstrate, a first patterned light-shielding layer, at least one secondpatterned light-shielding layer, at least one first pixel unit, at leastone second pixel unit, and a second substrate. The first substrate has afirst surface. The first patterned light-shielding layer includes aplurality of first openings and is disposed on the first surface of thefirst substrate. The second patterned light-shielding layer includes aplurality of second openings and is disposed on the first surface of thefirst substrate in the first patterned light-shielding layer. The firstpixel unit includes at least one first protrusion and at least onesecond protrusion. The first protrusion correspondingly covers the firstopenings of the first patterned light-shielding layer and a portion ofthe first patterned light-shielding layer. The second protrusion isdisposed in the first patterned light-shielding layer and the secondpatterned light-shielding layer. The second pixel unit includes at leastone third protrusion. The third protrusion correspondingly covers thesecond openings of the second patterned light-shielding layer and aportion of the second patterned light-shielding layer, wherein sizes ofthe second openings of the second patterned light-shielding layer aresmaller than sizes of the first openings of the first patternedlight-shielding layer. The second substrate has a second surface and isdisposed opposite to the first surface of the first substrate. Anoptical measuring apparatus for a structure is provided. The opticalmeasuring apparatus includes a positional movable platform, a lightsource, an operation processing unit, and a microscope lens, and themicroscope lens includes a dichroic minor, a first light detector, and asecond light detector. The positional movable platform is used to movethe microscope lens or the substrate of the tested display device toalign the microscope lens with the second patterned light-shieldinglayer on the substrate of the tested display device. The secondpatterned light-shielding layer is used as a reference plane and thelight source provides a parallel light beam passing through the dichroicmirror of the microscope lens. The parallel light beam is divided into ameasuring light beam and an interference light beam by the dichroicmirror. The measuring light beam irradiates the tested structure on thesubstrate of the display device or the reference plane and is reflectedto the microscope lens. Then, the reflected light is received andconverted into a reflected light signal by the first light detector, andthe interference light beam is received and converted into aninterference light signal by the second light detector. The stepsdescribed above are repeated to sequentially measure the firstprotrusion, the second protrusion, and the third protrusion on thesubstrate of the tested display device. Accordingly, a paired reflectedlight signal and interference light signal are obtained, respectively.Thereafter, the reflected light signals and the interference lightsignals are received and operated by the operation processing unit tooutput the height of the first protrusion, the second protrusion and thethird protrusion, respectively.

In the invention, the second patterned light-shielding layer provides alarger reflector plane than the first patterned light-shielding layer.Therefore, the measurement result of the height of the second patternedlight-shielding layer is more precise and more reproducible than themeasurement result of the height of the first patterned light-shieldinglayer, and picture quality and brightness of the display device are notsignificantly affected. Accordingly, a relative height of a photo spacercalculated according to the measurement result of the height of thesecond patterned light-shielding layer is more precise and morereproducible. Furthermore, more precise data is provided to control theprocesses which are adjusted by the parameters according to the sizemeasurement results, thus the production yield and the throughput areincreased.

In order to make the aforementioned and other features and advantages ofthe present invention more comprehensible, several embodimentsaccompanied with figures are described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a schematic view of a display device and an optical measuringapparatus for a surface structure according to prior art.

FIG. 2 is a schematic cross-sectional view of a height measurement of apatterned light-shielding layer of a display device according to priorart.

FIG. 3 is a schematic cross-sectional view of a height measurement of afirst protrusion of a display device according to prior art.

FIG. 4 is a schematic cross-sectional view of a height measurement of asecond protrusion of a display device according to prior art.

FIG. 5 is a schematic cross-sectional view of a display device accordingto a first embodiment of the invention.

FIG. 6 is a plane view of the first substrate 310 in FIG. 5 according toa second embodiment of the invention.

FIG. 7 is a schematic view of a height measurement according to thesecond embodiment of the invention.

DESCRIPTION OF EMBODIMENTS First Embodiment

FIG. 5 is a schematic cross-sectional view of a display device accordingto a first embodiment of the invention. Referring to FIG. 5, a displaydevice 300 of an embodiment of the invention is, for example, a liquidcrystal display device, and includes a first substrate 310, a firstpatterned light-shielding layer 322, at least one second patternedlight-shielding layer 332, at least one first pixel unit 326, at leastone second pixel unit 336, and a second substrate 340. The firstsubstrate 310 has a first surface 312. The first patternedlight-shielding layer 322 includes a plurality of first openings 324 andis disposed on the first surface 312 of the first substrate 310. Thesecond patterned light-shielding layer 332 includes a plurality ofsecond openings 334 and is disposed on the first surface 312 of thefirst substrate 310 in the first patterned light-shielding layer 322.The first pixel unit 326 includes at least one first red color filterlayer 326R, at least one first blue color filter layer 326B, and atleast one first green color filter layer 326G which cover the firstopenings 324 of the first patterned light-shielding layer 322 and aportion of the first patterned light-shielding layer 322, respectively.The first pixel unit 326 further includes at least one photo spacer 328disposed in the first patterned light-shielding layer 322 and the secondpatterned light-shielding layer 332. The second pixel unit 336 includesat least one second red color filter layer 336R, at least one secondblue color filter layer 336B, and at least one second green color filterlayer 336G which cover the second openings 334 of the second patternedlight-shielding layer 332 and a portion of the second patternedlight-shielding layer 332, respectively, wherein sizes of the secondopenings 334 of the second patterned light-shielding layer 332 aresmaller than sizes of the first openings 324 of the first patternedlight-shielding layer 322. The second substrate 340 has a second surface350 and is disposed opposite to the first surface 312 of the firstsubstrate 310.

In the invention, the second patterned light-shielding layer 332provides a larger reflector plane than the first patternedlight-shielding layer 322. Therefore, the measurement result of theheight of the second patterned light-shielding layer 332 is more preciseand more reproducible than that of the first patterned light-shieldinglayer 322. Accordingly, a relative height of the photo spacer 328calculated according to the measurement result of the second patternedlight-shielding layer 332 is more precise and more reproducible, andpicture quality and brightness of the display device are notsignificantly affected.

Second Embodiment

FIG. 6 is a plane view of the first substrate 310 in FIG. 5 according toa second embodiment of the invention. Referring to FIGS. 5 and 6, amethod of measuring a surface structure of a display device according tothe second embodiment of the invention includes the following steps.First, a display device 300 is provided. The display device 300 is, forexample, a liquid crystal display device, and includes a first substrate310, a first patterned light-shielding layer 322, at least one secondpatterned light-shielding layer 332, at least one first pixel unit 326,at least one second pixel unit 336, and a second substrate 340. Thefirst substrate 310 has a first surface 312. The first patternedlight-shielding layer 322 includes a plurality of first openings 324 andis disposed on the first surface 312 of the first substrate 310. Thesecond patterned light-shielding layer 332 includes a plurality ofsecond openings 334 and is disposed on the first surface 312 of thefirst substrate 310 in the first patterned light-shielding layer 322.The first pixel unit 326 includes at least one first red color filterlayer 326R, at least one first blue color filter layer 326B, and atleast one first green color filter layer 326G which cover the firstopenings 324 of the first patterned light-shielding layer 322 and aportion of the first patterned light-shielding layer 322, respectively.The first pixel unit 326 further includes at least one photo spacer 328disposed in the first patterned light-shielding layer 322 and the secondpatterned light-shielding layer 332. The second pixel unit 336 includesat least one second red color filter layer 336R, at least one secondblue color filter layer 336B, and at least one second green color filterlayer 336G which cover the second openings 334 of the second patternedlight-shielding layer 332 and a portion of the second patternedlight-shielding layer 332, respectively, wherein sizes of the secondopenings 334 of the second patterned light-shielding layer 332 aresmaller than sizes of the first openings 324 of the first patternedlight-shielding layer 322. The second substrate 340 has a second surface350 and is disposed opposite to the first surface 312 of the firstsubstrate 310.

Then, an optical measuring apparatus for a structure (not shown) isprovided. The optical measuring apparatus for a structure includes apositional movable platform (not shown), a light source (not shown), anoperation processing unit (not shown), and a microscope lens 360, andthe microscope lens 360 includes a dichroic mirror (not shown), a firstlight detector (not shown), and a second light detector (not shown).FIG. 7 is a schematic cross-sectional view of a height measurement ofthe display device along line A-A′ in FIG. 1 according to the secondembodiment of the invention. Referring to FIG. 7, the positional movableplatform is used to move the microscope lens 360 or the first substrate310 of the tested display device to align the microscope lens 360 withthe second patterned light-shielding layer 332 on the first substrate310 and posit the microscope lens 360 directly above the secondpatterned light-shielding layer 332. The second patternedlight-shielding layer 332 is used as a reference plane and the lightsource provides a parallel light beam passing through the dichroicmirror of the microscope lens 360. The parallel light beam is dividedinto a measuring light beam and an interference light beam by thedichroic mirror. The measuring light beam irradiates the testedstructure on the substrate of the display device or the reference planeand is reflected to the microscope lens 360. Then, the reflected lightis received and converted into a first reflected light signal by thefirst light detector, and the interference light beam is received andconverted into a first interference light signal by the second lightdetector. The steps described above are repeated to sequentially measurethe second red color filter layer 336R (or the second blue color filterlayer 336B, the second green color filter layer 336G) and the photospacer 328 of the second pixel unit 336 on the tested substrate toobtain a second reflected light signal, a second interference lightsignal, a third reflected light signal, and a third interference lightsignal. Thereafter, the first reflected and interference light signalsand the second reflected and interference light signals are received andoperated by the operation processing unit to output the height of thered color filter layer 336R of the second pixel unit 336. The firstreflected and interference light signals and the third reflected andinterference light signals are received and operated by the operationprocessing unit to output the height of the photo spacer 328. Then, asubtraction procedure is performed to subtract the height of the secondred color filter layer 336R from the height of the photo spacer 328 bythe operation processing unit and a relative height of the photo spacer328 is output.

In the invention, the second patterned light-shielding layer 332provides a larger reflector plane than the first patternedlight-shielding layer 322. Therefore, the measurement result of theheight of the second patterned light-shielding layer 332 is more preciseand more reproducible than the measurement result of the height of thefirst patterned light-shielding layer 322. Accordingly, the relativeheight of the photo spacer 328 calculated according to the measurementresult of the second patterned light-shielding layer 332 is more preciseand more reproducible, and picture quality and brightness of the displaydevice are not significantly affected.

In summary, the invention has the following advantages.

First, a larger light-shielding layer is disposed in part of the displayscreen to provide a sufficient measuring plane, and a low process yielddue to the difficulty in the measurement of the surface structure of thedisplay device with a high resolution is improved.

Second, since a larger light-shielding layer is disposed in part of thedisplay screen, picture quality and brightness of the display device arenot significantly affected.

Third, a reliable and effective method of measuring a surface structureof a display device is established.

Although the invention has been described with reference to theembodiments thereof, it will be apparent to one of the ordinary skillsin the art that modifications to the described embodiments may be madewithout departing from the spirit of the invention. Accordingly, thescope of the invention will be defined by the attached claims not by theabove detailed description.

1. A display device, comprising a first substrate, having a firstsurface; a first patterned light-shielding layer, having a plurality offirst openings and disposed on the first surface of the first substrate;at least one second patterned light-shielding layer, having a pluralityof second openings and disposed on the first surface of the firstsubstrate in the first patterned light-shielding layer; at least onefirst pixel unit, comprising: at least one first protrusion,correspondingly covering the first openings of the first patternedlight-shielding layer; and at least one second protrusion, disposed inthe first patterned light-shielding layer and the second patternedlight-shielding layer; at least one second pixel unit, comprising: atleast one third protrusion, correspondingly covering the second openingsof the second patterned light-shielding layer, wherein sizes of thesecond openings of the second patterned light-shielding layer aresmaller than sizes of the first openings of the first patternedlight-shielding layer; and a second substrate, having a second surfaceand disposed opposite to the first surface of the first substrate. 2.The display device as claimed in claim 1, wherein the first protrusioncomprises at least one red color filter layer, at least one blue colorfilter layer, and at least one green color filter layer.
 3. The displaydevice as claimed in claim 1, wherein the second protrusion comprises atleast one photo spacer.
 4. The display device as claimed in claim 1,wherein the third protrusion comprises at least one red color filterlayer, at least one blue color filter layer, and at least one greencolor filter layer.
 5. The display device as claimed in claim 1, whereinthe display device is a liquid crystal display device.
 6. The displaydevice as claimed in claim 1, wherein the display device is anelectrophoretic display device.
 7. A method of measuring a surfacestructure of a display device, comprising: providing a display device,the display device comprising: a first substrate, having a firstsurface; a first patterned light-shielding layer, having a plurality offirst openings and disposed on the first surface of the first substrate;at least one second patterned light-shielding layer, having a pluralityof second openings and disposed on the first surface of the firstsubstrate in the first patterned light-shielding layer; at least onefirst pixel unit, comprising: at least one first protrusion,correspondingly covering the first openings of the first patternedlight-shielding layer; and at least one second protrusion, disposed inthe first patterned light-shielding layer and the second patternedlight-shielding layer; at least one second pixel unit, comprising atleast one third protrusion, correspondingly covering the second openingsof the second patterned light-shielding layer, wherein sizes of thesecond openings of the second patterned light-shielding layer aresmaller than sizes of the first openings of the first patternedlight-shielding layer; and a second substrate, having a second surfaceand disposed opposite to the first surface of the first substrate;providing a measuring apparatus; measuring a first height of the firstprotrusion covering a surface of the second patterned light-shieldinglayer, the first height being a height difference between the secondpatterned light-shielding layer and the first protrusion; measuring asecond height of the second protrusion covering a surface of the secondpatterned light-shielding layer, the second height being a heightdifference between the second patterned light-shielding layer and thesecond protrusion; and calculating a third height which is a differencebetween the first height and the second height.
 8. The method ofmeasuring a surface structure of a display device as claimed in claim 7,wherein the first protrusion comprises at least one red color filterlayer, at least one blue color filter layer, and at least one greencolor filter layer.
 9. The method of measuring a surface structure of adisplay device as claimed in claim 7, wherein the second protrusioncomprises at least one photo spacer.
 10. The method of measuring asurface structure of a display device as claimed in claim 7, wherein thethird protrusion comprises at least one red color filter layer, at leastone blue color filter layer, and at least one green color filter layer.11. The method of measuring a surface structure of a display device asclaimed in claim 7, wherein the display device is a liquid crystaldisplay device.
 12. The method of measuring a surface structure of adisplay device as claimed in claim 7, wherein the display device is anelectrophoretic display device.
 13. The method of measuring a surfacestructure of a display device as claimed in claim 7, wherein themeasuring apparatus is a surface-contact measuring apparatus.
 14. Themethod of measuring a surface structure of a display device as claimedin claim 7, wherein the measuring apparatus is an optical non-contactmeasuring apparatus.
 15. The method of measuring a surface structure ofa display device as claimed in claim 7, wherein the measuring apparatusis an ultrasonic non-contact measuring apparatus.
 16. The method ofmeasuring a surface structure of a display device as claimed in claim 7,wherein the measuring apparatus is a sonic non-contact measuringapparatus.